Horizontal Layout (QHBoxLayout)

QHBoxLayout arranges widgets horizontally from left to right. Key methods include:

• addWidget(): Inserts widgets
• setSpacing(): Controls spacing between widgets

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QHBoxLayout, QPushButton

class HorizontalExample(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Horizontal Layout Example")
        hbox = QHBoxLayout()
        
        for i in range(1, 6):
            btn = QPushButton(f"Button {i}")
            hbox.addWidget(btn)
        
        hbox.setSpacing(5)
        self.setLayout(hbox)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = HorizontalExample()
    window.show()
    sys.exit(app.exec_())

Vertical Layout (QVBoxLayout)

QVBoxLayout arranges widgets vertically from top to bottom. It shares methods with QHBoxLayout.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QVBoxLayout, QPushButton

class VerticalExample(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Vertical Layout Example")
        self.resize(200, 200)
        vbox = QVBoxLayout()
        
        for i in range(1, 6):
            btn = QPushButton(f"Item {i}")
            vbox.addWidget(btn)
        
        self.setLayout(vbox)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = VerticalExample()
    window.show()
    sys.exit(app.exec_())

Grid Layout (QGridLayout)

QGridLayout positions widgets in a grid pattern with rows and columns.

Basic Grid Implementation

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QPushButton

class GridExample(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.initUI()

    def initUI(self):
        grid = QGridLayout()
        self.setLayout(grid)
        labels = ['Clear', 'Back', None, 'Close',
                  '7', '8', '9', '/',
                  '4', '5', '6', '*',
                  '1', '2', '3', '-',
                  '0', '.', '=', '+']
        
        positions = [(i, j) for i in range(5) for j in range(4)]
        
        for pos, label in zip(positions, labels):
            if label:
                button = QPushButton(label)
                grid.addWidget(button, pos[0], pos[1])
        
        self.setWindowTitle('Grid Layout Example')

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = GridExample()
    window.show()
    sys.exit(app.exec_())

Row and Column Spanning

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QLabel, QLineEdit, QTextEdit

class SpanningGrid(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.initUI()

    def initUI(self):
        grid = QGridLayout()
        grid.setSpacing(10)

        grid.addWidget(QLabel('Title:'), 0, 0)
        grid.addWidget(QLineEdit(), 0, 1)
        
        grid.addWidget(QLabel('Author:'), 1, 0)
        grid.addWidget(QLineEdit(), 1, 1)
        
        grid.addWidget(QLabel('Content:'), 2, 0)
        grid.addWidget(QTextEdit(), 2, 1, 3, 1)  # Span 3 rows, 1 column
        
        self.setLayout(grid)
        self.setWindowTitle('Grid Span Example')

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = SpanningGrid()
    window.show()
    sys.exit(app.exec_())

Form Layout (QFormLayout)

QFormLayout creates two-column forms with label-field pairs.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QFormLayout, QLineEdit, QLabel

class FormExample(QWidget):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setWindowTitle("Form Layout Example")
        self.resize(300, 150)
        form = QFormLayout()
        
        fields = [
            ("Field One:", QLineEdit()),
            ("Field Two:", QLineEdit()),
            ("Field Three:", QLineEdit())
        ]
        
        for label_text, input_widget in fields:
            form.addRow(QLabel(label_text), input_widget)
        
        self.setLayout(form)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = FormExample()
    window.show()
    sys.exit(app.exec_())

Nested Layout Techniques

Complex interfaces combine multiple layout types.

Layouts Within Layouts

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QHBoxLayout, QVBoxLayout, QGridLayout, QFormLayout, QPushButton

class NestedLayouts(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('Nested Layout Example')
        main_layout = QHBoxLayout()
        
        # Create different layout types
        h_layout = QHBoxLayout()
        v_layout = QVBoxLayout()
        grid_layout = QGridLayout()
        form_layout = QFormLayout()
        
        # Add widgets to layouts
        h_layout.addWidget(QPushButton("H1"))
        h_layout.addWidget(QPushButton("H2"))
        
        v_layout.addWidget(QPushButton("V1"))
        v_layout.addWidget(QPushButton("V2"))
        
        grid_layout.addWidget(QPushButton("G1"), 0, 0)
        grid_layout.addWidget(QPushButton("G2"), 0, 1)
        
        form_layout.addRow(QLabel("Label:"), QLineEdit())
        
        # Create container widgets
        h_container = QWidget()
        v_container = QWidget()
        g_container = QWidget()
        f_container = QWidget()
        
        h_container.setLayout(h_layout)
        v_container.setLayout(v_layout)
        g_container.setLayout(grid_layout)
        f_container.setLayout(form_layout)
        
        # Add containers to main layout
        main_layout.addWidget(h_container)
        main_layout.addWidget(v_container)
        main_layout.addWidget(g_container)
        main_layout.addWidget(f_container)
        
        self.setLayout(main_layout)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = NestedLayouts()
    window.show()
    sys.exit(app.exec_())

QSplitter Dynamic Layout

QSplitter provdies resizable sections with drag handles.

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QHBoxLayout, QSplitter, QFrame, QTextEdit
from PyQt5.QtCore import Qt

class SplitterExample(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        hbox = QHBoxLayout(self)
        self.setWindowTitle('QSplitter Example')
        self.setGeometry(300, 300, 450, 300)
        
        top_frame = QFrame()
        top_frame.setFrameShape(QFrame.StyledPanel)
        
        bottom_frame = QFrame()
        bottom_frame.setFrameShape(QFrame.StyledPanel)
        
        horizontal_split = QSplitter(Qt.Horizontal)
        editor = QTextEdit()
        horizontal_split.addWidget(top_frame)
        horizontal_split.addWidget(editor)
        horizontal_split.setSizes([150, 250])
        
        vertical_split = QSplitter(Qt.Vertical)
        vertical_split.addWidget(horizontal_split)
        vertical_split.addWidget(bottom_frame)
        
        hbox.addWidget(vertical_split)
        self.setLayout(hbox)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    demo = SplitterExample()
    demo.show()
    sys.exit(app.exec_())